How To Brew Old Coffee

You bought a solid bag of coffee some sunny Saturday afternoon with the intention of brewing before work. As the following weeks unraveled, you neglected that beautiful bag of beans. Next thing you know, your coffee is stale. You don’t want to waste those precious beans but don’t want a cup that tastes like old cigarettes. What to do?

There’s hope! Depending on how old the coffee is, you can actually salvage it into a pretty decent cup with some simple tricks.

Coffee will hold its flavor for 2-3 weeks (depending on type and roast). After 3 weeks however, coffee starts to go stale due to oxidization. Fruity taste notes are replaced with acidity and bitterness. BUT fear not, these two brew methods with help salvage coffee up to 5 weeks old:

Cold Brew

Cold brew is the most forgiving process for salvaging old beans. A study by Toddy estimates an average cup of cold brew with fresh beans is 67% less acidic than hot-brewed coffee. The 12 hour extraction slowly releases all of coffee’s wonderful fruity flavors while keeping those acidic aftertastes at bay. Because you are extracting coffee at lower temperatures, you avoid dissolving large amounts of coffee oils rich in acidic compounds.

For cold brew coffee, the recipe often depends on you’re brewer (and filter) of choice. For Duo, load the brew chamber up with 49-55 grams of coarsely ground coffee. Then fill the brew chamber up to the top (24oz) with room temperature water and let sit in the fridge overnight (12 hours).

Coarser Grind | Larger Doses

To brew old coffee hot, we recommend using a coarser grind and upping the dosage.

You’ll want a coarse grind (French press grind), and keep the temperature at a low 175 degrees fahrenheit (again, to keep the now more acidic oils at bay). If you usually use around 30 grams of coffee for a 12oz cup, shoot for around 50 grams.

For fresh coffee, depending on the beans and the gadget we’re using, we usually range between a 12:1 and 15:1 water to coffee ratio (15 grams of water to 1 gram of coffee). For old coffee we up the anti on the coffee side for a 7:1 ratio, so approx 50 grams of coffee for 350ml of water.

As always, experiment up and down what works for you and your brew method. If you have any questions, shoot us a note!